Epoxy Tips – Perfect Overhead Fillets

A fillet is a gutter-shaped bead of thickened epoxy that very effectively holds two pieces of rigid material together, most typically plywood strips. It is one of the most useful types of epoxy bonding technique for making strong and attractive joins.

When attempting to apply fillets on the underside of a boat’s cabin or decks, however, gravity can work against you. On the basics course, you’ll learn this clever technique that can put a fillet directly overhead with minimal fuss. The technique is also useful for achieving perfect fillets in other awkward, hard to reach areas.

Here’s how it’s done:

Mix the filleting compound together using the right ratios of resin, hardener and filler to create a ‘peanut butter’ consistency.

Take a piping bag or a polythene bag (supermarket food bags are ideal) and push some of the mixed filleting compound inside, getting it as close to the corner as possible.

Twist the bag up tight behind it to push the material further into the corner.

Snip the corner off the bag to make a hole that will match the size of the bead you want (you may well recognise this technique from when bakers ice a cake).

Squeeze the contents out of the bag to run a bead of thickened epoxy along the joint, aiming to keep the bead as consistent as possible.

Smooth the bead down with the curved end of a WEST SYSTEM 804 reusable mixing stick to push the mix firmly into the joint and create an even radius along the length of the fillet.

Tidy up any displaced material with the chisel end of the stick and you now have a perfect fillet, even when made directly overhead.